Based on what evidence? They're going to out tempo you and keep up with your value. And they're certainly going to push more damage. I can link a plethora of cards and explanations as to why if you can't decide that yourself based on what they're getting.
What is paladin or warrior going to do to keep up?
I think people are overestimating how much damage they can push. Their direct damage is pretty low for the mana it costs. And outside of Metamorphosis they don't have too, too much burst. The main concern I think is their ability to keep the board clear and their tempo plays, which generally are very powerful.
I'm much more nervous about how strong their tempo and control decks are than how their face or aggro decks are gonna be.